i would recomend 5 partitions 1) 20gigs for xp, 2)20gigs for osx 3)20gigs for linux, 4)1gig for linux swap, 5)the rest of your hard drive for storage. you can use just about any linux cd to partition the drive. then install xp on the first partition then install osx then install linux. linux install grub to the mbr so that you can boot to all 2 os's.